Pick an easy one. 3.租来的车是满箱油吗？还的时候也满箱就可以了吧？Normally, yes. If initially it is not full, they write on paper and u return with same gal level. Or they charge you for the gas (VERY expensive)

使用里程太多要另计费？This is very important. When you rent a car, before you sign ANY paperwork, make sure you know how many kilometers you could drive for free during the rental and how much they charge for extra kilometers after the limit. Sometimes, you could bargain with them. Of course, unlimited milage is perfect. If you cannot get this for free, trying to pay them $10/day to upgrade it to unlimited milage if you know you are going to drive a long way. I did that before.